Checking device



C. E. GALLEY -GHEGKING` DEVICE Oct. z, 1945.

Filed Marchl, 11945 Patented Oct. 2, 1945 This invention relates to thechecking of the dimensions of molded objects, particularly dentures, andto apparatus for that purpose.

In the customary denture processing a waxvcast or pattern is made ofthegums, the articial teeth are inserted for the proper occlusion or bite,and the cast is cased or lled out with wax. The wax case is theninvested with plaster in the lower half of a ask, the upper part or ringof the flask is mounted on the lower part, and filled with plaster, andthe lid placed on the flask. When the plaster has set, the ask parts areseparated, and the wax is boiled out, the teeth being held in place bythe plaster in the upper half of the flask. 'Ihe cavity left by removingthe wax is packed with the denture material, the flask is closed andlocked, and the material is hardened or set by immersing the flask inboiling water. In these various steps customarily followed, the teethare apt to be displaced, or there may be separation of the mold partsthrough overpacking or other cause with the formation of fins of thedenture material and a consequent change in dimensions and disturbanceof the occlusion.

The invention, in its application to dentures, provides for checking theocclusion and dimensions against the original Wax pattern invested inthe usual manner in the lower half of the flask. A plaque of plaster ofthe right consistency is poured on a piece of paper; and before theplaster sets, the wax denture, invested in the lower half of the ask, isinverted upon the plaque so that the tips of the teeth are embeddedtherein. When the plaster has set, the flask with the wax denture andthe plaque on the teeth are turned right side up. Another wad 0r bfallof soft plaster is then mixed and placed on the plaque. While theplaster is soft, a gauge, consisting of a perforated plate mounted onlegs spaced to contact the metal rim of the ask, is pressed down on thesoft ball until the legs rest firmly on the rim. When the plaster ballhas set, an accurate recording is obtained of the position of the teeth,the slope and the dimensions of the wax denture with relation to theflask in which it is invested.4 The gauge with its attached plasterimpression is then removed.

The usual practice of placing the top half of the flask and filling withplaster, removing the wax pattern and molding the denture is thenfollowed. When the denture is made, the plaster mold is forced out ofthe upper part of the flask and cut away from the denture, leaving themolded den- 'CharlesEf (Jralleyiy Chicago, Ill., assignerV to Luxene tInc. `,ac'orporation`of 1*)elaware` I f Applicata Marchal,1an;senainpgiisnzscf Y.

crains. (01:33 174)@l f ture mounted on the lower half of the flask justfaslthe, wanfjease or Apattern was originally.` .i11-

vested. The check is then applied to the denture. If there Ahas been nodistortion or shifting of the teeth or in the height or slope of thedenture, the gauge rests firmly on the rim of the flask with theimpression plaque in accurate contact with the teeth; on the other hand,any tooth displacement, spreading or change in height or slope isclearly made evident.

In the accompanying drawing there is illustrated a check, in which Fig.1 illustrates an impression sheet and a nished denture (or wax pattern)resting upon it;

Fig. 2 is a side view in partial cross section of the impressed sheet;

Fig. 3 is a top view of a gauge assembly; and

Fig. 4 is a side View of the assembly in position on the lower half ofthe flask. A

The impression material I0 is any suitable hardening plaster which issoft enough in consistency when applied to readily take the impressionI2 of the teeth of a denture pattern I I. Preferably the sheet isapplied to the pattern after it has been invested in plaster I4 in thelower half I3 of a flask as shown in Fig. 4. A sufficient amount of ahardening plaster wad 2| is placed on the positioned impression sheet.l

A gauge consists of a plate I5 supported by legs I6 threaded into theplate; lock nuts Il hold the legs in adjusted position. The metal rim ofthe ask part I3 forms a reference surface for contact bythe legs I6. Arim I8 with a llet I9 joining it to the plate I5 extends about the outeredge of the plate, and there are openings 20 in the plate. q

When the gauge is pressed on the soft wad of plaster the plaster exudesthrough the openings 20 and overflows into the space conned by the rimI8 to form a layer of-plaster 22 connected by the plaster slugs 23extending through the holes'20. y The plaster wad attaches itself to theimpression sheet, and on hardening locks the sheet to the gauge in theexact position it occupies on the pattern. When the case is replaced bythe molded denture, the latter occupies the position of the case withrelation to the lower half of the flask. It is then only necessary toremove the upper part of the flask and the plaster carried by it fromthe denture to have the denture in position for testing by setting thegauge legs on the, rim

of the flask and resting the impression on the'f If there has been nochange teeth of the denture. in the occlusion or dimensions theimpression ts the teeth and the legs of the gauge contact the rim; anydeparture in dimension or occlusion,

face, and testing the molded object replacing the4 Y pattern by theimpression secured to the gauge with the latter in position on the samereference surface.

2. Method of checking a molded object against a pattern from which it ismolded which comprises mounting the pattern with reference to a surface,making an impression of the pattern on a substance sufi'iciently plasticto take the impressionwithout distortion of l the pattern, vsecuririgthe impressed substance While in position on the pattern to a, gauge incontact with the reference surface, and testing the molded objectreplacing the pattern by the impression secured to the gauge With thelatter in position on the same reference surface.

3. Method of checking a molded denture against a case from which it ismolded which comprises investing thecase -in the lower half of a ask,impressing onthe case' a substance suiciently plastic to take theimpression without distortion of the case, positioning a gauge on therim of the flask half as a reference surface, securing the impressedsubstance in place on the case to the gauge, and testing the moldeddenture replacing the case before itsseparation from the lower half ofthe ask by the impression .secured to the gauge with the latter inposition on the rim of the ask.

CHARLES E. GALLEY.

